5 Poultry Sicknesses You’ve Likely Never Heard of

There are many different parasites, diseases, and disorders that can affect poultry. Some of them, such as mites, bumblefoot, impacted crop, and avian influenza, are familiar to many backyard flock owners. However, there are others that are less familiar to the average poultry owner, and some that seem to be a complete mystery. 

Here, Jeff Duguay, Ph.D. covers five poultry “sicknesses” you have likely never heard of. The information is drawn from his book, Parasites, Diseases, and Disorders of Poultry: Recognizing and Treating.

Poultry Sickness #1:

Hyaluronic Acid Crystals 

This first “sickness” isn’t a sickness at all; in fact, it is something that has medicinal uses. Perhaps you have heard of favus. Favus is a fungal disease that causes white chalky deposits, usually limited to the head, comb, and face of poultry.

It is zoonotic, meaning it can spread to people and cause ringworm. The average backyard poultry owner often misdiagnoses a rooster with hyaluronic acid crystals on its comb as having favus. This is because hyaluronic acid crystals are white and appear on the comb. 

Hyaluronic acid is a sugar molecule found in the combs of chickens, especially roosters. An increase in testosterone causes the comb to swell with hyaluronic acid, which may seep through the comb’s pores where it crystallizes. Although it resembles favus, it is harmless. 

Hyaluronic acid has medicinal benefits, including improving skin tone and skin hydration in people.

Poultry Sickness #2:

Avian Metapneumovirus 

• Considerable discharge from the eyes and nose
• Frothy eyes
• Conjunctivitis

Later stages include:

• Facial swelling
• Coughing
• Sneezing

Reports show mortality rates reaching 50%. Otherwise healthy birds may recover within 7–10 days. Wild birds are believed to be natural reservoirs for this disease. There is no treatment.

Poultry Sickness #3:

Derzsy’s Disease 

Also known as Muscovy Duck parvovirus and waterfowl parvovirus, is a highly contagious disease of domestic goslings and Muscovy ducklings. The disease spreads from the breeder to the egg (known as vertical transmission) as well as through direct contact (known as horizontal transmission) with infected birds or contact with infected feces, often in the feed or water.

Infected birds excrete the virus in large amounts in their feces, resulting in rapid horizontal spread. Mortality may reach 100% in waterfowl less than a week old.

Birds 2-4 weeks old typically have:

• Nasal discharge
• Profuse white diarrhea
• Weakness
• Conjunctivitis
• Loss of natal down

Mortality can reach 10% in older birds. Older birds do not show symptoms of Derzsy’s disease.

Birds that survive frequently become carriers and transmit the virus horizontally and vertically. Wild geese using the same pasture or pond as domestic geese and Muscovy ducks may be a source of infection. There is no treatment for Derzsy’s disease.

Poultry Sickness #4:

Gout 

Although you have likely heard of gout, did you know that gout can affect poultry? There are two forms of gout: Articular, which occurs in the joints, and Visceral gout, which affects the kidneys and other organs. 

Articular gout occurs when uric acid and urates are deposited in the leg or wrist joints. The joints become red, swollen, tender, and warm to the touch, causing a reluctance to walk. White urate deposits in the joint often appear easily through the skin.

Kidney failure causes visceral gout. Birds with visceral gout usually don’t show symptoms before death or appear emaciated.

Causes of gout include feed with high levels of calcium and vitamin D3 and low levels of phosphorus, especially when birds are still growing. High amounts of sodium bicarbonate, salt, and protein (more than 30%) in the feed, as well as dehydration, can also lead to gout. 

Feeding a high calcium diet to non-laying chickens (chicks, pullets, roosters, hens that no longer lay) can cause kidney damage, leading to gout. If your bird has gout, you should reduce the amount of calcium, salt, vitamin D3, and protein in the diet and increase the amount of phosphorus. 

Do not feed a layer ration to non-laying poultry. Supporting proper nutrient absorption and balance through the diet is critical, and products like Buff Clucks Herb Supplement can help birds make better use of the nutrients they receive when feed formulations are adjusted.

Poultry Sickness #5:

Hypocalcemia 

Vitamin D3 is required for normal absorption and metabolism of calcium and phosphorus. Vitamin D3 deficiency in laying hens can result in poor egg shell quality (thin or soft shelled), even though the diet may be well supplied with calcium and phosphorus. 

A condition known as hypocalcemia, or calcium tetany (paralysis), may occur in hens with a diet deficient in vitamin D3. Hypocalcemia occurs when a chicken’s blood calcium levels are dangerously low. This syndrome happens suddenly. 

Hens suffering from hypocalcemia may exhibit:

• Panting
• Spread wings
• Prostration
• May be unable to stand

They may go from appearing deathly ill to perfectly normal within hours (sometimes a few days) of laying an egg.

Hypocalcemia can, however, result in mortality. Poultry can synthesize vitamin D3 in their non-feathered skin areas, but require adequate exposure to UV light to do so. 

Mortality can be reduced in hens suffering from hypocalcemia by administering vitamin D3 in the drinking water for three consecutive days. If you discover a hen that you believe is suffering from hypocalcemia, you can dissolve a Tums® tablet (calcium carbonate) in a few mL of water and administer it orally into the crop. 

If hypocalcemia is the culprit, the hen should recover quickly, within 30 minutes. 

Jeff Duguay, Ph.D., is a poultry owner, exhibitor, and author of poultry books. Jeff has written 10 books on poultry, including Parasites, Diseases, and Disorders of Poultry: Recognizing and Treating. Jeff’s books are available at cluckerbooks.com